In a food processor, blend together 2 cups of all-purpose flour, ½ teaspoon of salt, and 2 tablespoons of sugar. Pulse in 1 cup of cold, cubed butter until the mixture resembles coarse crumbs. Gradually add 4-6 tablespoons of ice water, pulsing until the dough just comes together. Divide the dough in half, flatten into disks, wrap in plastic, and chill for about 1 hour.

While the dough chills, wash and slice about 4 cups of ripe plums, discarding the pits. In a large bowl, combine the sliced plums with ½ cup of sugar and 1 teaspoon of ground cinnamon. Toss gently to coat, then let the mixture sit for about 20 minutes.

Once chilled, take one disk of pie dough and roll it out on a floured surface to fit a 15x10 inch jelly roll pan. Carefully fit the dough into the pan, and prick the bottom with a fork. Spread a layer of cherry preserves evenly over the uncooked crust, followed by the prepared plum filling.

Preheat your oven to 375°F (190°C). Brush the edges of the crust lightly with melted butter. Place the pie in the oven and bake for about 50-60 minutes, or until golden brown and bubbling.

Once baked, remove from the oven and cool in the pan for at least 30 minutes. Serve slices warm, optionally with a scoop of vanilla ice cream or whipped cream.